This invention relates to the field of data recording/playback and, more particularly, to apparatus for facilitating the handling and transport of data storage disks, e.g. optical and magnetic hard disks.
The desirability of handling high density data storage disks without contacting their delicate data recording surfaces is manifest. With this in mind, it is known, for example, to rotatably mount such disks in rigid cartridges from which they are never removed, even during periods of use. See, for example, the protective cartridge disclosed in U.S. Pat. No. 4,433,410. Such a cartridge includes a plurality of spring-loaded latches which engage the enclosed disk at spaced locations about the disk periphery. Such latches are intended to precisely locate the disk within the cartridge so that it may be reliably positioned relative to a rotatable spindle in a disk drive, and to prevent the disk from shifting laterally or axially within the cartridge and thereby contacting the cartridge walls. During use of the disk tapered pins, associated with the disk drive unit, are moved in a direction to engage and release the spring-loaded latches, displacing such latches to a position which permits unimpeded disk rotation.
Protective cartridges of the above type are particularly useful in carefully controlled environments where dust and other contaminating substances are not present. However, because such cartridges must be provided with a relatively large central opening through which a disk drive spindle can enter the cartridge and rotatably drive the disk within, such cartridges can give rise to contamination problems in less controlled environments.
To avoid the contamination disadvantages of cartridges of the above type, it is also known in the art to house high density data storage disks in rigid jackets or caddies which allow removal of the disk only after the caddy has been accepted into the controlled environment of a disk drive unit. See, for example, the protective optical disk package disclosed in U.S. Pat. No. 4,352,174. Here, the disk drive unit comprises a mechanism for entering the disk's protective jacket and physically gripping the disk so that when the jacket is withdrawn from the disk drive unit, the disk is retained within the drive unit. To assure reliable gripping of the disk, the periphery is provided with a raised bead which can be more readily engaged.
As another means for facilitating the removal of a data storage disk from its protective jacket or caddy, as well as to facilitate the subsequent handling of such a disk, it is known to capture the disk at its periphery by a so called "disk carrier." Such a device typically comprises a rigid, planar frame, often generally rectangular in shape, having a circular aperture slightly larger in diameter than that of the disk. A plurality of radially extending tabs extend inwardly from the aperture wall and support the disk at spaced locations around the disk periphery. See, for example, the disk carriers disclosed in U.S. Pat. Nos. 4,419,060 and 4,481,617. Such disk carriers are normally totally enclosed by a protective caddy, and removal of the disk from the caddy is achieved by engaging and withdrawing the disk carrier.
In disk carriers of the above type, there is, by necessity, a relatively loose fit between the disk and the disk-capturing features of the carrier. This loose fit is necessitated by the fact that the disk is intended to rotate within the carrier frame. During use, the carrier is precisely located relative to a disk drive spindle so that the disk can be rotatably driven without contacting any of the carrier's disk-capturing features. Obviously, to assure non-contact between the disk and carrier during disk rotation, the disk must have a certain amount of freedom to move both axially and laterally within the carrier frame. Such freedom of movement is potentially harmful to a captured disk, particularly to those disks of a more fragile nature. Moreover, such carriers cannot precisely locate their captured disk relative to the axis of rotation of a drive spindle. No matter how precisely the carrier is located within the disk drive unit, the lateral position of the disk can vary substantially, due to its freedom to move within the carrier frame. Thus, the disk drive unit must be capable of accepting a disk which is substantially displaced from a desired axis of rotation.